xref: /netbsd-src/sys/net/if_vlan.c (revision 23c8222edbfb0f0932d88a8351d3a0cf817dfb9e)
1 /*	$NetBSD: if_vlan.c,v 1.41 2004/07/08 19:09:12 mycroft Exp $	*/
2 
3 /*-
4  * Copyright (c) 2000, 2001 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Andrew Doran, and by Jason R. Thorpe of Zembu Labs, Inc.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *	This product includes software developed by the NetBSD
21  *	Foundation, Inc. and its contributors.
22  * 4. Neither the name of The NetBSD Foundation nor the names of its
23  *    contributors may be used to endorse or promote products derived
24  *    from this software without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36  * POSSIBILITY OF SUCH DAMAGE.
37  */
38 
39 /*
40  * Copyright 1998 Massachusetts Institute of Technology
41  *
42  * Permission to use, copy, modify, and distribute this software and
43  * its documentation for any purpose and without fee is hereby
44  * granted, provided that both the above copyright notice and this
45  * permission notice appear in all copies, that both the above
46  * copyright notice and this permission notice appear in all
47  * supporting documentation, and that the name of M.I.T. not be used
48  * in advertising or publicity pertaining to distribution of the
49  * software without specific, written prior permission.  M.I.T. makes
50  * no representations about the suitability of this software for any
51  * purpose.  It is provided "as is" without express or implied
52  * warranty.
53  *
54  * THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''.  M.I.T. DISCLAIMS
55  * ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE,
56  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
57  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT
58  * SHALL M.I.T. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
59  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
60  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
61  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
62  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
63  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
64  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
65  * SUCH DAMAGE.
66  *
67  * from FreeBSD: if_vlan.c,v 1.16 2000/03/26 15:21:40 charnier Exp
68  * via OpenBSD: if_vlan.c,v 1.4 2000/05/15 19:15:00 chris Exp
69  */
70 
71 /*
72  * if_vlan.c - pseudo-device driver for IEEE 802.1Q virtual LANs.  Might be
73  * extended some day to also handle IEEE 802.1P priority tagging.  This is
74  * sort of sneaky in the implementation, since we need to pretend to be
75  * enough of an Ethernet implementation to make ARP work.  The way we do
76  * this is by telling everyone that we are an Ethernet interface, and then
77  * catch the packets that ether_output() left on our output queue when it
78  * calls if_start(), rewrite them for use by the real outgoing interface,
79  * and ask it to send them.
80  *
81  * TODO:
82  *
83  *	- Need some way to notify vlan interfaces when the parent
84  *	  interface changes MTU.
85  */
86 
87 #include <sys/cdefs.h>
88 __KERNEL_RCSID(0, "$NetBSD: if_vlan.c,v 1.41 2004/07/08 19:09:12 mycroft Exp $");
89 
90 #include "opt_inet.h"
91 #include "bpfilter.h"
92 
93 #include <sys/param.h>
94 #include <sys/kernel.h>
95 #include <sys/mbuf.h>
96 #include <sys/queue.h>
97 #include <sys/socket.h>
98 #include <sys/sockio.h>
99 #include <sys/systm.h>
100 #include <sys/proc.h>
101 
102 #if NBPFILTER > 0
103 #include <net/bpf.h>
104 #endif
105 #include <net/if.h>
106 #include <net/if_dl.h>
107 #include <net/if_types.h>
108 #include <net/if_ether.h>
109 #include <net/if_vlanvar.h>
110 
111 #ifdef INET
112 #include <netinet/in.h>
113 #include <netinet/if_inarp.h>
114 #endif
115 
116 struct vlan_mc_entry {
117 	LIST_ENTRY(vlan_mc_entry)	mc_entries;
118 	/*
119 	 * A key to identify this entry.  The mc_addr below can't be
120 	 * used since multiple sockaddr may mapped into the same
121 	 * ether_multi (e.g., AF_UNSPEC).
122 	 */
123 	union {
124 		struct ether_multi	*mcu_enm;
125 	} mc_u;
126 	struct sockaddr_storage		mc_addr;
127 };
128 
129 #define	mc_enm		mc_u.mcu_enm
130 
131 struct ifvlan {
132 	union {
133 		struct ethercom ifvu_ec;
134 	} ifv_u;
135 	struct ifnet *ifv_p;	/* parent interface of this vlan */
136 	struct ifv_linkmib {
137 		const struct vlan_multisw *ifvm_msw;
138 		int	ifvm_encaplen;	/* encapsulation length */
139 		int	ifvm_mtufudge;	/* MTU fudged by this much */
140 		int	ifvm_mintu;	/* min transmission unit */
141 		u_int16_t ifvm_proto;	/* encapsulation ethertype */
142 		u_int16_t ifvm_tag;	/* tag to apply on packets */
143 	} ifv_mib;
144 	LIST_HEAD(__vlan_mchead, vlan_mc_entry) ifv_mc_listhead;
145 	LIST_ENTRY(ifvlan) ifv_list;
146 	int ifv_flags;
147 };
148 
149 #define	IFVF_PROMISC	0x01		/* promiscuous mode enabled */
150 
151 #define	ifv_ec		ifv_u.ifvu_ec
152 
153 #define	ifv_if		ifv_ec.ec_if
154 
155 #define	ifv_msw		ifv_mib.ifvm_msw
156 #define	ifv_encaplen	ifv_mib.ifvm_encaplen
157 #define	ifv_mtufudge	ifv_mib.ifvm_mtufudge
158 #define	ifv_mintu	ifv_mib.ifvm_mintu
159 #define	ifv_tag		ifv_mib.ifvm_tag
160 
161 struct vlan_multisw {
162 	int	(*vmsw_addmulti)(struct ifvlan *, struct ifreq *);
163 	int	(*vmsw_delmulti)(struct ifvlan *, struct ifreq *);
164 	void	(*vmsw_purgemulti)(struct ifvlan *);
165 };
166 
167 static int	vlan_ether_addmulti(struct ifvlan *, struct ifreq *);
168 static int	vlan_ether_delmulti(struct ifvlan *, struct ifreq *);
169 static void	vlan_ether_purgemulti(struct ifvlan *);
170 
171 const struct vlan_multisw vlan_ether_multisw = {
172 	vlan_ether_addmulti,
173 	vlan_ether_delmulti,
174 	vlan_ether_purgemulti,
175 };
176 
177 static int	vlan_clone_create(struct if_clone *, int);
178 static void	vlan_clone_destroy(struct ifnet *);
179 static int	vlan_config(struct ifvlan *, struct ifnet *);
180 static int	vlan_ioctl(struct ifnet *, u_long, caddr_t);
181 static void	vlan_start(struct ifnet *);
182 static void	vlan_unconfig(struct ifnet *);
183 
184 void		vlanattach(int);
185 
186 /* XXX This should be a hash table with the tag as the basis of the key. */
187 static LIST_HEAD(, ifvlan) ifv_list;
188 
189 struct if_clone vlan_cloner =
190     IF_CLONE_INITIALIZER("vlan", vlan_clone_create, vlan_clone_destroy);
191 
192 /* Used to pad ethernet frames with < ETHER_MIN_LEN bytes */
193 static char vlan_zero_pad_buff[ETHER_MIN_LEN];
194 
195 void
196 vlanattach(int n)
197 {
198 
199 	LIST_INIT(&ifv_list);
200 	if_clone_attach(&vlan_cloner);
201 }
202 
203 static void
204 vlan_reset_linkname(struct ifnet *ifp)
205 {
206 
207 	/*
208 	 * We start out with a "802.1Q VLAN" type and zero-length
209 	 * addresses.  When we attach to a parent interface, we
210 	 * inherit its type, address length, address, and data link
211 	 * type.
212 	 */
213 
214 	ifp->if_type = IFT_L2VLAN;
215 	ifp->if_addrlen = 0;
216 	ifp->if_dlt = DLT_NULL;
217 	if_alloc_sadl(ifp);
218 }
219 
220 static int
221 vlan_clone_create(struct if_clone *ifc, int unit)
222 {
223 	struct ifvlan *ifv;
224 	struct ifnet *ifp;
225 	int s;
226 
227 	ifv = malloc(sizeof(struct ifvlan), M_DEVBUF, M_WAITOK);
228 	memset(ifv, 0, sizeof(struct ifvlan));
229 	ifp = &ifv->ifv_if;
230 	LIST_INIT(&ifv->ifv_mc_listhead);
231 
232 	s = splnet();
233 	LIST_INSERT_HEAD(&ifv_list, ifv, ifv_list);
234 	splx(s);
235 
236 	snprintf(ifp->if_xname, sizeof(ifp->if_xname), "%s%d", ifc->ifc_name,
237 	    unit);
238 	ifp->if_softc = ifv;
239 	ifp->if_flags = IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST;
240 	ifp->if_start = vlan_start;
241 	ifp->if_ioctl = vlan_ioctl;
242 	IFQ_SET_READY(&ifp->if_snd);
243 
244 	if_attach(ifp);
245 	vlan_reset_linkname(ifp);
246 
247 	return (0);
248 }
249 
250 static void
251 vlan_clone_destroy(struct ifnet *ifp)
252 {
253 	struct ifvlan *ifv = ifp->if_softc;
254 	int s;
255 
256 	s = splnet();
257 	LIST_REMOVE(ifv, ifv_list);
258 	vlan_unconfig(ifp);
259 	splx(s);
260 
261 	if_detach(ifp);
262 	free(ifv, M_DEVBUF);
263 }
264 
265 /*
266  * Configure a VLAN interface.  Must be called at splnet().
267  */
268 static int
269 vlan_config(struct ifvlan *ifv, struct ifnet *p)
270 {
271 	struct ifnet *ifp = &ifv->ifv_if;
272 	int error;
273 
274 	if (ifv->ifv_p != NULL)
275 		return (EBUSY);
276 
277 	switch (p->if_type) {
278 	case IFT_ETHER:
279 	    {
280 		struct ethercom *ec = (void *) p;
281 
282 		ifv->ifv_msw = &vlan_ether_multisw;
283 		ifv->ifv_encaplen = ETHER_VLAN_ENCAP_LEN;
284 		ifv->ifv_mintu = ETHERMIN;
285 
286 		/*
287 		 * If the parent supports the VLAN_MTU capability,
288 		 * i.e. can Tx/Rx larger than ETHER_MAX_LEN frames,
289 		 * enable it.
290 		 */
291 		if (ec->ec_nvlans++ == 0 &&
292 		    (ec->ec_capabilities & ETHERCAP_VLAN_MTU) != 0) {
293 			/*
294 			 * Enable Tx/Rx of VLAN-sized frames.
295 			 */
296 			ec->ec_capenable |= ETHERCAP_VLAN_MTU;
297 			if (p->if_flags & IFF_UP) {
298 				struct ifreq ifr;
299 
300 				ifr.ifr_flags = p->if_flags;
301 				error = (*p->if_ioctl)(p, SIOCSIFFLAGS,
302 				    (caddr_t) &ifr);
303 				if (error) {
304 					if (ec->ec_nvlans-- == 1)
305 						ec->ec_capenable &=
306 						    ~ETHERCAP_VLAN_MTU;
307 					return (error);
308 				}
309 			}
310 			ifv->ifv_mtufudge = 0;
311 		} else if ((ec->ec_capabilities & ETHERCAP_VLAN_MTU) == 0) {
312 			/*
313 			 * Fudge the MTU by the encapsulation size.  This
314 			 * makes us incompatible with strictly compliant
315 			 * 802.1Q implementations, but allows us to use
316 			 * the feature with other NetBSD implementations,
317 			 * which might still be useful.
318 			 */
319 			ifv->ifv_mtufudge = ifv->ifv_encaplen;
320 		}
321 
322 		/*
323 		 * If the parent interface can do hardware-assisted
324 		 * VLAN encapsulation, then propagate its hardware-
325 		 * assisted checksumming flags.
326 		 */
327 		if (ec->ec_capabilities & ETHERCAP_VLAN_HWTAGGING)
328 			ifp->if_capabilities = p->if_capabilities &
329 			    (IFCAP_CSUM_IPv4|IFCAP_CSUM_TCPv4|
330 			     IFCAP_CSUM_UDPv4|IFCAP_CSUM_TCPv6|
331 			     IFCAP_CSUM_UDPv6);
332 
333 		/*
334 		 * We inherit the parent's Ethernet address.
335 		 */
336 		ether_ifattach(ifp, LLADDR(p->if_sadl));
337 		ifp->if_hdrlen = sizeof(struct ether_vlan_header); /* XXX? */
338 		break;
339 	    }
340 
341 	default:
342 		return (EPROTONOSUPPORT);
343 	}
344 
345 	ifv->ifv_p = p;
346 	ifv->ifv_if.if_mtu = p->if_mtu - ifv->ifv_mtufudge;
347 	ifv->ifv_if.if_flags = p->if_flags &
348 	    (IFF_UP | IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST);
349 
350 	/*
351 	 * Inherit the if_type from the parent.  This allows us
352 	 * to participate in bridges of that type.
353 	 */
354 	ifv->ifv_if.if_type = p->if_type;
355 
356 	return (0);
357 }
358 
359 /*
360  * Unconfigure a VLAN interface.  Must be called at splnet().
361  */
362 static void
363 vlan_unconfig(struct ifnet *ifp)
364 {
365 	struct ifvlan *ifv = ifp->if_softc;
366 
367 	if (ifv->ifv_p == NULL)
368 		return;
369 
370 	/*
371  	 * Since the interface is being unconfigured, we need to empty the
372 	 * list of multicast groups that we may have joined while we were
373 	 * alive and remove them from the parent's list also.
374 	 */
375 	(*ifv->ifv_msw->vmsw_purgemulti)(ifv);
376 
377 	/* Disconnect from parent. */
378 	switch (ifv->ifv_p->if_type) {
379 	case IFT_ETHER:
380 	    {
381 		struct ethercom *ec = (void *) ifv->ifv_p;
382 
383 		if (ec->ec_nvlans-- == 1) {
384 			/*
385 			 * Disable Tx/Rx of VLAN-sized frames.
386 			 */
387 			ec->ec_capenable &= ~ETHERCAP_VLAN_MTU;
388 			if (ifv->ifv_p->if_flags & IFF_UP) {
389 				struct ifreq ifr;
390 
391 				ifr.ifr_flags = ifv->ifv_p->if_flags;
392 				(void) (*ifv->ifv_p->if_ioctl)(ifv->ifv_p,
393 				    SIOCSIFFLAGS, (caddr_t) &ifr);
394 			}
395 		}
396 
397 		ether_ifdetach(ifp);
398 		vlan_reset_linkname(ifp);
399 		break;
400 	    }
401 
402 #ifdef DIAGNOSTIC
403 	default:
404 		panic("vlan_unconfig: impossible");
405 #endif
406 	}
407 
408 	ifv->ifv_p = NULL;
409 	ifv->ifv_if.if_mtu = 0;
410 	ifv->ifv_flags = 0;
411 
412 	if_down(ifp);
413 	ifp->if_flags &= ~(IFF_UP|IFF_RUNNING);
414 	ifp->if_capabilities = 0;
415 }
416 
417 /*
418  * Called when a parent interface is detaching; destroy any VLAN
419  * configuration for the parent interface.
420  */
421 void
422 vlan_ifdetach(struct ifnet *p)
423 {
424 	struct ifvlan *ifv;
425 	int s;
426 
427 	s = splnet();
428 
429 	for (ifv = LIST_FIRST(&ifv_list); ifv != NULL;
430 	     ifv = LIST_NEXT(ifv, ifv_list)) {
431 		if (ifv->ifv_p == p)
432 			vlan_unconfig(&ifv->ifv_if);
433 	}
434 
435 	splx(s);
436 }
437 
438 static int
439 vlan_set_promisc(struct ifnet *ifp)
440 {
441 	struct ifvlan *ifv = ifp->if_softc;
442 	int error = 0;
443 
444 	if ((ifp->if_flags & IFF_PROMISC) != 0) {
445 		if ((ifv->ifv_flags & IFVF_PROMISC) == 0) {
446 			error = ifpromisc(ifv->ifv_p, 1);
447 			if (error == 0)
448 				ifv->ifv_flags |= IFVF_PROMISC;
449 		}
450 	} else {
451 		if ((ifv->ifv_flags & IFVF_PROMISC) != 0) {
452 			error = ifpromisc(ifv->ifv_p, 0);
453 			if (error == 0)
454 				ifv->ifv_flags &= ~IFVF_PROMISC;
455 		}
456 	}
457 
458 	return (error);
459 }
460 
461 static int
462 vlan_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
463 {
464 	struct proc *p = curproc;	/* XXX */
465 	struct ifvlan *ifv = ifp->if_softc;
466 	struct ifaddr *ifa = (struct ifaddr *) data;
467 	struct ifreq *ifr = (struct ifreq *) data;
468 	struct ifnet *pr;
469 	struct vlanreq vlr;
470 	struct sockaddr *sa;
471 	int s, error = 0;
472 
473 	s = splnet();
474 
475 	switch (cmd) {
476 	case SIOCSIFADDR:
477 		if (ifv->ifv_p != NULL) {
478 			ifp->if_flags |= IFF_UP;
479 
480 			switch (ifa->ifa_addr->sa_family) {
481 #ifdef INET
482 			case AF_INET:
483 				arp_ifinit(ifp, ifa);
484 				break;
485 #endif
486 			default:
487 				break;
488 			}
489 		} else {
490 			error = EINVAL;
491 		}
492 		break;
493 
494 	case SIOCGIFADDR:
495 		sa = (struct sockaddr *)&ifr->ifr_data;
496 		memcpy(sa->sa_data, LLADDR(ifp->if_sadl), ifp->if_addrlen);
497 		break;
498 
499 	case SIOCSIFMTU:
500 		if (ifv->ifv_p != NULL) {
501 			if (ifr->ifr_mtu >
502 			     (ifv->ifv_p->if_mtu - ifv->ifv_mtufudge) ||
503 			    ifr->ifr_mtu <
504 			     (ifv->ifv_mintu - ifv->ifv_mtufudge))
505 				error = EINVAL;
506 			else
507 				ifp->if_mtu = ifr->ifr_mtu;
508 		} else
509 			error = EINVAL;
510 		break;
511 
512 	case SIOCSETVLAN:
513 		if ((error = suser(p->p_ucred, &p->p_acflag)) != 0)
514 			break;
515 		if ((error = copyin(ifr->ifr_data, &vlr, sizeof(vlr))) != 0)
516 			break;
517 		if (vlr.vlr_parent[0] == '\0') {
518 			vlan_unconfig(ifp);
519 			break;
520 		}
521 		if (vlr.vlr_tag != EVL_VLANOFTAG(vlr.vlr_tag)) {
522 			error = EINVAL;		 /* check for valid tag */
523 			break;
524 		}
525 		if ((pr = ifunit(vlr.vlr_parent)) == 0) {
526 			error = ENOENT;
527 			break;
528 		}
529 		if ((error = vlan_config(ifv, pr)) != 0)
530 			break;
531 		ifv->ifv_tag = vlr.vlr_tag;
532 		ifp->if_flags |= IFF_RUNNING;
533 
534 		/* Update promiscuous mode, if necessary. */
535 		vlan_set_promisc(ifp);
536 		break;
537 
538 	case SIOCGETVLAN:
539 		memset(&vlr, 0, sizeof(vlr));
540 		if (ifv->ifv_p != NULL) {
541 			snprintf(vlr.vlr_parent, sizeof(vlr.vlr_parent), "%s",
542 			    ifv->ifv_p->if_xname);
543 			vlr.vlr_tag = ifv->ifv_tag;
544 		}
545 		error = copyout(&vlr, ifr->ifr_data, sizeof(vlr));
546 		break;
547 
548 	case SIOCSIFFLAGS:
549 		/*
550 		 * For promiscuous mode, we enable promiscuous mode on
551 		 * the parent if we need promiscuous on the VLAN interface.
552 		 */
553 		if (ifv->ifv_p != NULL)
554 			error = vlan_set_promisc(ifp);
555 		break;
556 
557 	case SIOCADDMULTI:
558 		error = (ifv->ifv_p != NULL) ?
559 		    (*ifv->ifv_msw->vmsw_addmulti)(ifv, ifr) : EINVAL;
560 		break;
561 
562 	case SIOCDELMULTI:
563 		error = (ifv->ifv_p != NULL) ?
564 		    (*ifv->ifv_msw->vmsw_delmulti)(ifv, ifr) : EINVAL;
565 		break;
566 
567 	default:
568 		error = EINVAL;
569 	}
570 
571 	splx(s);
572 
573 	return (error);
574 }
575 
576 static int
577 vlan_ether_addmulti(struct ifvlan *ifv, struct ifreq *ifr)
578 {
579 	struct vlan_mc_entry *mc;
580 	u_int8_t addrlo[ETHER_ADDR_LEN], addrhi[ETHER_ADDR_LEN];
581 	int error;
582 
583 	if (ifr->ifr_addr.sa_len > sizeof(struct sockaddr_storage))
584 		return (EINVAL);
585 
586 	error = ether_addmulti(ifr, &ifv->ifv_ec);
587 	if (error != ENETRESET)
588 		return (error);
589 
590 	/*
591 	 * This is new multicast address.  We have to tell parent
592 	 * about it.  Also, remember this multicast address so that
593 	 * we can delete them on unconfigure.
594 	 */
595 	MALLOC(mc, struct vlan_mc_entry *, sizeof(struct vlan_mc_entry),
596 	    M_DEVBUF, M_NOWAIT);
597 	if (mc == NULL) {
598 		error = ENOMEM;
599 		goto alloc_failed;
600 	}
601 
602 	/*
603 	 * As ether_addmulti() returns ENETRESET, following two
604 	 * statement shouldn't fail.
605 	 */
606 	(void)ether_multiaddr(&ifr->ifr_addr, addrlo, addrhi);
607 	ETHER_LOOKUP_MULTI(addrlo, addrhi, &ifv->ifv_ec, mc->mc_enm);
608 	memcpy(&mc->mc_addr, &ifr->ifr_addr, ifr->ifr_addr.sa_len);
609 	LIST_INSERT_HEAD(&ifv->ifv_mc_listhead, mc, mc_entries);
610 
611 	error = (*ifv->ifv_p->if_ioctl)(ifv->ifv_p, SIOCADDMULTI,
612 	    (caddr_t)ifr);
613 	if (error != 0)
614 		goto ioctl_failed;
615 	return (error);
616 
617  ioctl_failed:
618 	LIST_REMOVE(mc, mc_entries);
619 	FREE(mc, M_DEVBUF);
620  alloc_failed:
621 	(void)ether_delmulti(ifr, &ifv->ifv_ec);
622 	return (error);
623 }
624 
625 static int
626 vlan_ether_delmulti(struct ifvlan *ifv, struct ifreq *ifr)
627 {
628 	struct ether_multi *enm;
629 	struct vlan_mc_entry *mc;
630 	u_int8_t addrlo[ETHER_ADDR_LEN], addrhi[ETHER_ADDR_LEN];
631 	int error;
632 
633 	/*
634 	 * Find a key to lookup vlan_mc_entry.  We have to do this
635 	 * before calling ether_delmulti for obvious reason.
636 	 */
637 	if ((error = ether_multiaddr(&ifr->ifr_addr, addrlo, addrhi)) != 0)
638 		return (error);
639 	ETHER_LOOKUP_MULTI(addrlo, addrhi, &ifv->ifv_ec, enm);
640 
641 	error = ether_delmulti(ifr, &ifv->ifv_ec);
642 	if (error != ENETRESET)
643 		return (error);
644 
645 	/* We no longer use this multicast address.  Tell parent so. */
646 	error = (*ifv->ifv_p->if_ioctl)(ifv->ifv_p, SIOCDELMULTI,
647 	    (caddr_t)ifr);
648 	if (error == 0) {
649 		/* And forget about this address. */
650 		for (mc = LIST_FIRST(&ifv->ifv_mc_listhead); mc != NULL;
651 		    mc = LIST_NEXT(mc, mc_entries)) {
652 			if (mc->mc_enm == enm) {
653 				LIST_REMOVE(mc, mc_entries);
654 				FREE(mc, M_DEVBUF);
655 				break;
656 			}
657 		}
658 		KASSERT(mc != NULL);
659 	} else
660 		(void)ether_addmulti(ifr, &ifv->ifv_ec);
661 	return (error);
662 }
663 
664 /*
665  * Delete any multicast address we have asked to add from parent
666  * interface.  Called when the vlan is being unconfigured.
667  */
668 static void
669 vlan_ether_purgemulti(struct ifvlan *ifv)
670 {
671 	struct ifnet *ifp = ifv->ifv_p;		/* Parent. */
672 	struct vlan_mc_entry *mc;
673 	union {
674 		struct ifreq ifreq;
675 		struct {
676 			char ifr_name[IFNAMSIZ];
677 			struct sockaddr_storage ifr_ss;
678 		} ifreq_storage;
679 	} ifreq;
680 	struct ifreq *ifr = &ifreq.ifreq;
681 
682 	memcpy(ifr->ifr_name, ifp->if_xname, IFNAMSIZ);
683 	while ((mc = LIST_FIRST(&ifv->ifv_mc_listhead)) != NULL) {
684 		memcpy(&ifr->ifr_addr, &mc->mc_addr, mc->mc_addr.ss_len);
685 		(void)(*ifp->if_ioctl)(ifp, SIOCDELMULTI, (caddr_t)ifr);
686 		LIST_REMOVE(mc, mc_entries);
687 		FREE(mc, M_DEVBUF);
688 	}
689 }
690 
691 static void
692 vlan_start(struct ifnet *ifp)
693 {
694 	struct ifvlan *ifv = ifp->if_softc;
695 	struct ifnet *p = ifv->ifv_p;
696 	struct ethercom *ec = (void *) ifv->ifv_p;
697 	struct mbuf *m;
698 	int error;
699 	ALTQ_DECL(struct altq_pktattr pktattr;)
700 
701 	ifp->if_flags |= IFF_OACTIVE;
702 
703 	for (;;) {
704 		IFQ_DEQUEUE(&ifp->if_snd, m);
705 		if (m == NULL)
706 			break;
707 
708 #ifdef ALTQ
709 		/*
710 		 * If ALTQ is enabled on the parent interface, do
711 		 * classification; the queueing discipline might
712 		 * not require classification, but might require
713 		 * the address family/header pointer in the pktattr.
714 		 */
715 		if (ALTQ_IS_ENABLED(&p->if_snd)) {
716 			switch (p->if_type) {
717 			case IFT_ETHER:
718 				altq_etherclassify(&p->if_snd, m, &pktattr);
719 				break;
720 #ifdef DIAGNOSTIC
721 			default:
722 				panic("vlan_start: impossible (altq)");
723 #endif
724 			}
725 		}
726 #endif /* ALTQ */
727 
728 #if NBPFILTER > 0
729 		if (ifp->if_bpf)
730 			bpf_mtap(ifp->if_bpf, m);
731 #endif
732 		/*
733 		 * If the parent can insert the tag itself, just mark
734 		 * the tag in the mbuf header.
735 		 */
736 		if (ec->ec_capabilities & ETHERCAP_VLAN_HWTAGGING) {
737 			struct m_tag *mtag;
738 
739 			mtag = m_tag_get(PACKET_TAG_VLAN, sizeof(u_int),
740 			    M_NOWAIT);
741 			if (mtag == NULL) {
742 				ifp->if_oerrors++;
743 				m_freem(m);
744 				continue;
745 			}
746 			*(u_int *)(mtag + 1) = ifv->ifv_tag;
747 			m_tag_prepend(m, mtag);
748 		} else {
749 			/*
750 			 * insert the tag ourselves
751 			 */
752 			M_PREPEND(m, ifv->ifv_encaplen, M_DONTWAIT);
753 			if (m == NULL) {
754 				printf("%s: unable to prepend encap header",
755 				    ifv->ifv_p->if_xname);
756 				ifp->if_oerrors++;
757 				continue;
758 			}
759 
760 			switch (p->if_type) {
761 			case IFT_ETHER:
762 			    {
763 				struct ether_vlan_header *evl;
764 
765 				if (m->m_len < sizeof(struct ether_vlan_header))
766 					m = m_pullup(m,
767 					    sizeof(struct ether_vlan_header));
768 				if (m == NULL) {
769 					printf("%s: unable to pullup encap "
770 					    "header", ifv->ifv_p->if_xname);
771 					ifp->if_oerrors++;
772 					continue;
773 				}
774 
775 				/*
776 				 * Transform the Ethernet header into an
777 				 * Ethernet header with 802.1Q encapsulation.
778 				 */
779 				memmove(mtod(m, caddr_t),
780 				    mtod(m, caddr_t) + ifv->ifv_encaplen,
781 				    sizeof(struct ether_header));
782 				evl = mtod(m, struct ether_vlan_header *);
783 				evl->evl_proto = evl->evl_encap_proto;
784 				evl->evl_encap_proto = htons(ETHERTYPE_VLAN);
785 				evl->evl_tag = htons(ifv->ifv_tag);
786 
787 				/*
788 				 * To cater for VLAN-aware layer 2 ethernet
789 				 * switches which may need to strip the tag
790 				 * before forwarding the packet, make sure
791 				 * the packet+tag is at least 68 bytes long.
792 				 * This is necessary because our parent will
793 				 * only pad to 64 bytes (ETHER_MIN_LEN) and
794 				 * some switches will not pad by themselves
795 				 * after deleting a tag.
796 				 */
797 				if (m->m_pkthdr.len <
798 				    (ETHER_MIN_LEN + ETHER_VLAN_ENCAP_LEN)) {
799 					m_copyback(m, m->m_pkthdr.len,
800 					    (ETHER_MIN_LEN +
801 					     ETHER_VLAN_ENCAP_LEN) -
802 					     m->m_pkthdr.len,
803 					    vlan_zero_pad_buff);
804 				}
805 				break;
806 			    }
807 
808 #ifdef DIAGNOSTIC
809 			default:
810 				panic("vlan_start: impossible");
811 #endif
812 			}
813 		}
814 
815 		/*
816 		 * Send it, precisely as the parent's output routine
817 		 * would have.  We are already running at splnet.
818 		 */
819 		IFQ_ENQUEUE(&p->if_snd, m, &pktattr, error);
820 		if (error) {
821 			/* mbuf is already freed */
822 			ifp->if_oerrors++;
823 			continue;
824 		}
825 
826 		ifp->if_opackets++;
827 		if ((p->if_flags & (IFF_RUNNING|IFF_OACTIVE)) == IFF_RUNNING)
828 			(*p->if_start)(p);
829 	}
830 
831 	ifp->if_flags &= ~IFF_OACTIVE;
832 }
833 
834 /*
835  * Given an Ethernet frame, find a valid vlan interface corresponding to the
836  * given source interface and tag, then run the real packet through the
837  * parent's input routine.
838  */
839 void
840 vlan_input(struct ifnet *ifp, struct mbuf *m)
841 {
842 	struct ifvlan *ifv;
843 	u_int tag;
844 	struct m_tag *mtag;
845 
846 	mtag = m_tag_find(m, PACKET_TAG_VLAN, NULL);
847 	if (mtag != NULL) {
848 		/* m contains a normal ethernet frame, the tag is in mtag */
849 		tag = *(u_int *)(mtag + 1);
850 		m_tag_delete(m, mtag);
851 		for (ifv = LIST_FIRST(&ifv_list); ifv != NULL;
852 		    ifv = LIST_NEXT(ifv, ifv_list))
853 			if (ifp == ifv->ifv_p && tag == ifv->ifv_tag)
854 				break;
855 	} else {
856 		switch (ifp->if_type) {
857 		case IFT_ETHER:
858 		    {
859 			struct ether_vlan_header *evl;
860 
861 			if (m->m_len < sizeof(struct ether_vlan_header) &&
862 			    (m = m_pullup(m,
863 			     sizeof(struct ether_vlan_header))) == NULL) {
864 				printf("%s: no memory for VLAN header, "
865 				    "dropping packet.\n", ifp->if_xname);
866 				return;
867 			}
868 			evl = mtod(m, struct ether_vlan_header *);
869 			KASSERT(ntohs(evl->evl_encap_proto) == ETHERTYPE_VLAN);
870 
871 			tag = EVL_VLANOFTAG(ntohs(evl->evl_tag));
872 
873 			/*
874 			 * Restore the original ethertype.  We'll remove
875 			 * the encapsulation after we've found the vlan
876 			 * interface corresponding to the tag.
877 			 */
878 			evl->evl_encap_proto = evl->evl_proto;
879 			break;
880 		    }
881 
882 		default:
883 			tag = (u_int) -1;	/* XXX GCC */
884 #ifdef DIAGNOSTIC
885 			panic("vlan_input: impossible");
886 #endif
887 		}
888 
889 		for (ifv = LIST_FIRST(&ifv_list); ifv != NULL;
890 		     ifv = LIST_NEXT(ifv, ifv_list))
891 			if (ifp == ifv->ifv_p && tag == ifv->ifv_tag)
892 				break;
893 
894 
895 		/*
896 		 * Now, remove the encapsulation header.  The original
897 		 * header has already been fixed up above.
898 		 */
899 		if (ifv) {
900 			memmove(mtod(m, caddr_t) + ifv->ifv_encaplen,
901 			    mtod(m, caddr_t), sizeof(struct ether_header));
902 			m_adj(m, ifv->ifv_encaplen);
903 		}
904 	}
905 
906 	if (ifv == NULL ||
907 	    (ifv->ifv_if.if_flags & (IFF_UP|IFF_RUNNING)) !=
908 	     (IFF_UP|IFF_RUNNING)) {
909 		m_freem(m);
910 		ifp->if_noproto++;
911 		return;
912 	}
913 	m->m_pkthdr.rcvif = &ifv->ifv_if;
914 	ifv->ifv_if.if_ipackets++;
915 
916 #if NBPFILTER > 0
917 	if (ifv->ifv_if.if_bpf)
918 		bpf_mtap(ifv->ifv_if.if_bpf, m);
919 #endif
920 
921 	/* Pass it back through the parent's input routine. */
922 	(*ifp->if_input)(&ifv->ifv_if, m);
923 }
924